Wet Chemical extinguishers are generally used in kitchens where cooking oils are used. The reason for this is when dealing with hot oil a specialist extinguisher is more effective and safer as it puts the fire out in a different way, When using a wet chemical on hot oil a reaction occurs called saponification which turns the oil into a soap like substance. There are different sizes of wet chemical and the size you require will depend on the surface area of your fryers. Wet chemicals are also safe to use on class A fires.